Here we go again... NO!
By supporting the death penalty you are saying you find it acceptable to put innocent men to death. Any system, however perfect, is operated by human beings who will make mistakes, how do you take back execution when you find out the guy didn't do it after all?
Also, in the US it costs a great deal more to execute a prisoner than to imprison them for life. Handing down a death sentence means a massive and lengthy legal process of appeals/assessment of (paradoxical) fitness for execution and a bunch of other things that take years and costs millions. It's much cheaper just to lock them up until they die of their own accord, people are also more accepting of this as it retains the hope of proving the defendant's innocence, even if that's never going to happen.